Tuning fails for positive ions at the 1700 range but works fine for positive ions at 3200. It works fine for all ranges with negative ions.

When the tuning is done at 3200 (+) everything is fine. When I change it to tune at 1700 (+) the masses are reasonably accurate. After it gets to the third mass (620) it appears that the entire spectrum shifts by about 1.5 AMU and the tuning fails. There is no problem at either mass range in negative ions. As of now we can do all our work at 3200 but I'm wondering if there is another problem. Phone support suggests the Medusa??